JPH11268858A - Sheet stack height detector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To detect sheet stack height with little noise and vibration and without interrupting replenishment and taking-out of sheets, using a compact structure. SOLUTION: A controllable step motor 120 is mounted on a sheet stack height detector. A tentacle 10 is moved from an initial position (y, z') capable of being preset to a detecting position (y', z) toward a sheet stack 21 by a stepper motor 120, and the height of the stack 21 is determined based on the stepping rotational speed of the detected stepper motor 120.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for detecting the height of a stack of sheets stacked on an input or output sheet storage tray in an apparatus such as a printer or a copying machine.

[0002]

2. Description of the Related Art In printers and copying machines, a plurality of sheet storage trays are used. For example, a printer as a computer output device has at least a tray for storing paper to be copied and a tray for storing copied paper. Similarly, a copier includes a tray for storing at least a document, a tray for storing paper to be copied, and a tray for storing copied paper. The present invention is applicable to all of these trays, and generally relates to a device for detecting the height of a sheet stack in a tray for storing a sheet stack in which a plurality of sheets such as paper are stacked. It is.

A device for detecting the height of a sheet stack is conventionally known. For example, EP-A-768263 discloses a conventional sheet stack height detecting device. The sheet stack height detecting device disclosed in this European Patent Publication is adapted to detect the height of a sheet stack in a tray for collecting at least one output sheet as an output unit of a printer. This sheet stack height detection device utilizes a tentacle in the form of a pivotable tentacle-type bracket that periodically rotates to a detection position facing the sheet stack. Then, a sensor such as an electronic sensor detects the position of the tentacle above the sheet stack and somewhere along the stacking direction in which the sheets are sequentially stacked, thereby increasing the height of the sheet stack. Is to be detected.

A tentacle / holding finger is provided at a first end of the tentacle-shaped bracket in the above-mentioned known device, and the tentacle / holding finger is reciprocally movable about its rotation center axis by a microprocessor. It is designed to be rotated by a magnet. The reciprocating armature of the reciprocating magnet is connected to the second end of the tentacle-shaped bracket opposite to the first end via a spring element. A switching tab for activating the sensor is arranged at the second end of the bracket.

The tentacle bracket, sensor and reciprocating magnet are located outside the collection tray and in front of the end surface wall of the tray, ie, in front of the front alignment edge of the paper sheet discharged to the collection tray. Are located in Therefore, when the tentacle-shaped bracket is in the initial position, the fingers are located above the front area of the sheet stack and separated from the front area, and the switching tab is located outside the detection area of the sensor. I'm coming. During the detection cycle, the tentacle bracket pivots through the slot formed in the end surface wall to the collection tray, with the fingers facing the sheet stack, with the switching tabs facing the sensor. Pivot to This sensor is activated only when the stack of sheets in the collecting tray reaches the maximum allowable height, or is covered by a switching tab, so that a signal is supplied to the control unit to stop the paper feed. Has become.

In another embodiment disclosed in the above-mentioned European Patent Publication, sensor means (a plurality of sensors) for detecting an intermediate value of the height of the sheet stack or a plurality of switching tabs (corresponding to the sensor means) are provided. (The corresponding number of slots are installed together.)
Is used. In this case, a sensor is located on the bottom or support surface of the collection tray to detect the first sheet in the collection tray.

[0007]

Since the sheet stack height detecting apparatus having the above-described structure and other existing sheet stack height detecting apparatuses use a reciprocally movable magnet, the apparatus can move. There is a problem that considerable vibration and noise are generated each time the operation is performed. In addition, these conventionally known sheet stack height detecting devices require complicated detection of the intermediate value of the height of the sheet stacks and detection of the first sheet in the collection tray. There is also the problem of having to use sensor means. In addition, a means for detecting the height of the sheet stack is provided in a take-out conveyance path of the sheet stack after the work has been completed (i.e., in the case of a printer, all of which has been printed), or unloading or loading of the collection tray. There is also a problem that it has to be placed in the storage area.

In view of the above problems, the height of the sheet stack at the input or output trays of the apparatus is simple to manufacture, compact in construction, cost effective and relatively easy to handle. There has conventionally been a demand for a sheet stack height detecting device capable of detecting the sheet stack height.

[0009]

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide a sheet stack height detecting apparatus which has almost no noise or vibration and has a compact structure. It is another object of the present invention to provide a sheet stack height detector that can operate in an automated environment without interrupting sheet replenishment and removal.

Further, one of the main points of the present invention is to use a controllable stepper motor for moving the touch device from a predetermined initial position toward the sheet stack and to the detection position. . By using this stepper motor,
The height of the sheet stack can be determined based on the step rotation speed of the motor detected from the initial position until the detection position of the tentacle is recognized.

A sheet stack height detecting apparatus according to the present invention, which achieves the above-mentioned objects, is periodically controlled by a drive unit and a control unit, and is arranged along a sheet stacking direction. It has a tentacle that can be moved to the upper detection position. The sensor detects the height of the sheet stack and recognizes the detection position of the tentacle. In addition, the sheet stack height detecting device of the present invention is provided with a controllable stepper motor, and this motor is used to move the tentacle to a predetermined initial position toward the sheet stack.
(y, z ') is moved to the detection position (y', z). Therefore, the sheet stack height can be obtained based on the step rotation speed of the stepper motor detected from the initial position until the detection position of the tentacle is recognized.

Various advantages can be obtained by configuring the sheet stack height detecting apparatus of the present invention as described above.
First, by using a stepper motor itself, or by using a control cam having a cam plate and a stepper motor together, the rotation step interval from one step position of the motor to the next step position is determined.
It can be smaller than the minimum thickness of the particular type of sheet utilized. Second, the detection cycle of the tentacles is automatically or automatically dependent on the number of sheets placed on or taken out of the collection tray and on the thickness of the particular type of sheet utilized. It can be adjusted manually.

Further, the touch device is operated by a stepper motor.
Alternatively, it is convenient to move by a stepper motor via a cam plate, so that the linear speed of the tentacle gradually decreases in the area immediately before the detection position, the initial position, and the unload / place position. The tentacle moves with a speed profile.

Further, in the present invention, it is desirable that an output signal from a sensor arranged to detect the height of the sheet stack is detected by a control unit including a microprocessor, a counter, and an arithmetic unit. .

It is preferable that the touch device has a touch finger, and the touch finger is arranged on a support which is moved in the stacking direction by a stepper motor. The tactile finger of the tentacle with the support thus arranged is moved back and forth along the direction of movement of the support against the spring element, so that the tip of the touch comes into contact with the sheet stack. ing.

Further, it is desirable that the drive unit including the touch device, the sensor, and the stepper motor and the radial cam is arranged above the sheet stack and above the tray. In addition, a means for aligning the uppermost sheet of the sheet stack or temporarily holding the discharged or placed sheet is provided, and the means is determined based on the height of the determined sheet stack. It is desirable to be able to move to a predetermined working position.

[0017]

BRIEF DESCRIPTION OF THE DRAWINGS FIG.
One embodiment of the sheet stack height detecting device of the present invention will be described in detail. First, in FIGS. 1 to 3, reference numeral 1 denotes a sheet stack height detecting apparatus according to the present invention. The detecting device 1 is provided with an inclined loading tray or a discharge tray 2 (hereinafter referred to as a "collecting tray") of an apparatus such as a copying machine or a printer.
), The paper is fed or ejected almost horizontally.
(Hereinafter, “feed” is used including both operations.) The height of the stack 21 of the vertically stacked sheets is detected.

As clearly shown in FIG. 3, the detecting device 1 includes a sheet stack body that is periodically moved by a drive unit 12 and a control unit (not shown) to a detection position in the sheet stacking direction. The tentacle 10 is controlled and driven with respect to 21. The sensor 11 is a sheet stack 21
And detects the detection state of the tentacle 10. It should be noted that it is obvious to those skilled in the art that the sheet stack height detecting device 1 of the present invention can be used for various devices, in particular, a sheet handling device such as a copying machine or a printer (not shown). Is preferably used to collect output sheets as a result of a user specified printing or copying operation.

Further, the sheet stack height detecting apparatus 1 of the present invention can be applied to a case where the sheet output to the collecting tray is a single sheet.
It is possible to use even a stack of multiple stacks,
It will be clear to those skilled in the art. In any case, the detection device 1 is not limited to the collecting tray shown in FIG. 3 as a collecting tray, but also a non-tilting horizontal collecting tray or a vertical collecting tray (the stacking direction of sheets is The horizontal direction and the moving direction of the tentacle are also horizontal directions).

In FIGS. 1 to 3, the detection device 1 at the detection positions y 'and z includes a holder 122, a drive unit 12,
It has a tentacle 10, a sensor 11, etc., all of which are arranged above the collecting tray 2, and thus the sheet stack 21. In particular, as shown in FIGS. 1 and 3, the drive unit 12 is provided with a stepper motor 120 that can be controlled by a control unit that controls the movement of the touch device 10. The tentacle 10 is movable from a predetermined initial position y, z ′ with respect to the sheet stack 21 to a detection position y ′, z.
While the tentacle 10 is moving in this way, the sheet stack 2
The height of 1 is determined based on the step rotation speed of the stepper motor detected by the control unit from the initial position until the detection position of the touch device 10 is recognized.

2 and 3, the drive unit 12
A control cam 123 and a radial cam 125 are arranged above the control cam 123. The control cam 123 is rotatable about a rotation axis 126, and the radial cam 125 is driven by a stepper motor 1 via a drive pinion 121 and a gear 124.
20 and is integrally connected to the control cam 123. As shown in FIG. 1, the touch device 10 includes a support 105, and the support 105
Is moved in the stacking direction of sheets by the stepper motor 1120 and the control cam 123.
In addition, a touch finger 100 is provided on the touch device 10. The touch finger 100 moves along the support 1
5, the probe 101 is moved in the sheet stacking direction, and the probe 101, which is the tip of the touch finger 100, is pressed against the sheet stack 21.

As shown in FIGS. 2 and 3, the support 105
The upper finger 100 is a spring element 1 such as a torsion spring.
The sheet is urged toward the sheet stack 21 by 04 and is brought into contact with the locking piece 109 on the support 105 to be set at the initial position y. The movement of the touch finger 100 is also defined by the movement of the support 105 in the direction of the sheet stack 21, that is, the touch finger 100 contacts the sheet stack 21.
Alternatively, it is possible to move to a detection position y ′ in contact with the sheet support surface 20 of the collection tray 2. This touch finger 1
When 00 is in the aforementioned position, the first sensor 110 of the sensor means 11 on the support 105 is activated by the switching tab 102 on the opposite side of the probe 101 of the touch finger 100. In this configuration, the touch finger 100 is supported by the support 105 so as to be rotatable about a center axis 103, and the switching tab 102 is provided at one end of the touch finger 100 on the opposite side of the probe 101. ing.

In FIGS. 1 and 2, the support 105 is
The control cam 123 is in the form of a suspended U-shaped member that is rotatable around a rotation pin 106 at a height of a rotation axis 126 of the control cam 123. An operating lever 107 which is in contact with an upper outer rim of the control cam 123, that is, a radial cam 125, is provided at an upper end or a rear of the support 105. As clearly shown in FIG. 3, the support 105 carrying the tentacle 10 and the first sensor 110 has a lower end 108.
Rotate in a state of facing the sheet stack 21.

The radial cam 125 of the control cam 123 for controlling the stepper motor 120 together with the operating lever 107
Constitutes means for rotating the support 105 upward from the detection position z to the initial position z '. When the support 105 is rotated in one direction, the touch finger 100 is separated from one or both of the sheet stack 21 and the sheet support surface 20 of the collection tray 2. Also, the support 105
Is rotated in the other direction, the support 105 carrying the tentacle 10 and the sensor 11 is rotated downward and returned to the detection position z under the control of the radial cam 125 by its own weight. . In addition, the support 105 that carries the touch device 10 and the first sensor 110 is rotated to the uppermost position for one or both of the sheet stack 21 and the collection tray 2, that is, the unloading position z ″. It can move.

In FIGS. 2 and 3, a second position for the unloading or input position 211 is located near the control cam 123 so that the initial position z 'of the support and the unloading or input position z "can be recognized. A sensor 128 or a third sensor (not shown) is provided, and a control cam 123 is provided.
Further, a switching cam 127 having at least one detection mark 129 for the second and third sensors is added. In this sense, the sensor 11 or the sensor 11
Reference numerals 0 and 128 each have a conventionally known configuration such as an electro-optical type, an electromechanical type, or a magnetic type.

Referring to FIG. 3, the step rotation speed of stepper motor 120 for determining the height of sheet stack 21 can be detected as described above. In particular, this step speed corresponds to the second sensor 128 characterizing the initial position z ′.
Or between the output signal from the second sensor characterizing the extraction or input position z "and the output signal from the first sensor characterizing the detection positions y ', z. This step speed is determined. To do so, a control unit including a microprocessor, a counting device, an arithmetic device, and a memory is used.

In this sense, the rotation step interval of the stepper motor 120 is controlled by the radial cam 12 of the control cam 123.
5 together with the minimum thickness of the particular type of sheet used. In addition, the detection cycle of the touch device 10 can be automatically adjusted by a control program of the control unit. This can be achieved by automatically detecting the number of sheets fed to the stack height detecting device 1 or the collection tray 2 and the type of the sheets, or by, for example, checking the sheet type and the number of sheets specified by the user. Can be achieved manually by typing The detection cycle is a time between detection operations according to the number of sheets fed to the collection tray 2 and the thickness of a specific type of sheet used.

Although not shown, in another embodiment of the invention, a toothed rack or support linearly movable toward the sheet stack (either biased by a spring element or The linearly movable movable touch device 10 equipped with a linearly movable movable finger without using a spring element)
0 is directly driven. In this alternative embodiment, the rotation step interval of the stepper motor 120 is smaller than the minimum thickness of the particular type of sheet utilized. The tentacle 10 has such a velocity that the linear velocity of the tentacle gradually decreases in the detection position y ′, z, the initial position y, z ′, and the area immediately before the extraction or input position y, z ″. It can be moved by the stepper motor 120 in the profile.

Referring back to FIG. 1 to FIG. 3, the support 105 is provided with not only the touch finger 100 but also another functional unit, for example, an alignment unit 4 having means for aligning the uppermost sheet of the stack 21. Have been. Also, this support 105
Alternatively, a holding unit 3 having means for temporarily holding the fed sheet may be carried. Further, the support 105 may be provided with a deflection panel 5 for deflecting and guiding the uppermost sheet fed to the sheet stack 21. In another embodiment (not shown), only one of the two functional units 3 and 4 is provided. In yet another embodiment, both functional units 3, 4 are provided on a respective support (not shown) separate from the haptic support 105, which is also not shown.

Referring to FIG. 1, the holding unit 3 is provided with a drive mechanism for itself. The drive mechanism includes a drive motor 34 having drive rollers 33 attached to both ends of a drive shaft, a drive belt 32, and an output drive roller 31 attached to the lower end 108 of the support 105. Each output drive roller 31 is provided with a separation finger 30, and this drive roller 31 is driven by a drive motor 34. In order to hold and collect the sheet, the output drive roller 31 is rotated at the front edge of the collection tray 2 toward the sheet conveyance path, and the collection tray 2 is emptied at that time. Then, the output drive roller 31 comes to face the recess formed in the sheet support surface 20.

As shown in FIG. 1, the aligning unit 4 also has a driving mechanism for itself, and this driving mechanism includes a driving motor 44 having a driving roller 43, a driving belt 42, and a support 105. And an output drive roller 41 attached to the lower end. A rotatable elastic impeller 41 is connected to the output drive roller 41, and the impeller 41 applies a frictional force to the uppermost sheet of the sheet stack 21 to slightly move the sheet so that the side of the collection tray 2 is moved. Lock plate 2
3 and the edge of the sheet corresponding to the front locking plate 22 are brought into contact with each other.

As shown in FIG. 1, the holding means 3 (separating finger 30) and the aligning means 4 (impeller 41)
1 can be set to respective predetermined operation positions. These predetermined operation positions are determined according to the height of the sheet stack in the collection tray 2 determined by the control unit. The drive unit 12 (the stepper motor 120 and the control cam 123) of the tentacle 10 (the support body 105 and the tentacle 100) constitutes a means for setting the positions of the holding means 3 and the alignment means 4. Means 3, 4
Corresponds to the predetermined initial positions y, z ′ of the tentacles 10, 100, 105 where the probe 101 of the touch finger 100 is separated from the sheet stack 21.

The radial cam 125 of the control cam 123 is
As shown in FIG. 3, it has a plurality of radial cam parts connected to each other, and these cam parts are matched with the linear movement sequence of the tentacle 10, the aligning means 4 and the holding means 3. The cam section for the tentacle 10 has a detection position y ', z, an initial position y, z' and an unloading or input position y ', z "to reduce the linear velocity as described above. The slope is gentle.

The operation of the sheet stack height detecting device of the present invention will be described below. When the detection device 1 is in an idle state (this state is not shown), the tentacle 10 is controlled by the control unit to be in a predetermined initial position by the stepper motor 120, and the aligning means 4 is in the empty collection tray 2 Are set at predetermined operation positions facing upward.
A predetermined number of sheets are fed to the collection tray 2 and stacked
The detection of the height of the stack 21 after is formed is achieved through the following operation steps.

A) The stepper motor 120 is activated by the control program of the control unit, and the tentacle 10 (the support and the tentacle 100) is moved from the first predetermined initial position separated from the sheet stack 21 toward the stack. And move at a relatively low speed along the stacking direction. b) the second sensor 128 characterizing the initial position y, z '
Starts counting of stepping pulses for controlling the stepper motor based on the output signal from. c) increasing the speed of the stepper motor via a control program or a control unit according to a defined speed profile. d) Just before reaching the detection position on the sheet stack, the speed of the stepper motor is gradually reduced according to a specified speed profile. e) The counting of the output signals from the first sensor characterizing the detection positions y 'and z is terminated. f) Stop the stepper motor and store the count value so far in the memory of the control unit. g) The computer of the control unit subtracts the count value detected at that time from the step count value (reference step count value) detected when the collection tray is empty, that is, calculates the height of the sheet stack by calculating the difference. I do. h) The control unit rotates the stepper motor in the opposite direction and returns the tentacle to its original initial position in the previous speed profile.

As another method, the last return step h can be performed as follows. h1) Return the haptics to a new initial position separated by a distance equal to the difference from the previous stack height by an amount equal to the difference. h2) Increase the reference step count by an amount equal to the difference and make it the new reference step count.

As another method, the radial cam 12 is used.
3, the starting of the stepper motor 120 and the counting of the stepping pulse are simultaneously performed starting from the initial position determined by the original reference step count value or the recalculated reference step count value without using the second sensor 128. You may do so.

[0038]

As described above, the sheet stack height detecting apparatus according to the present invention hardly generates noise or vibration,
Further, there is an advantage that the configuration is compact. Also,
The sheet stack height can be detected in an automated environment without interrupting sheet replenishment and removal.

[Brief description of the drawings]

FIG. 1 is a perspective view of a sheet stack height detecting apparatus according to the present invention, shown together with a sheet holding unit and a sheet aligning unit.

FIG. 2 is an enlarged front view of a portion indicated by A in FIG. 1 in the sheet stack height detecting device of FIG. 1 in which the sheet holding unit and the sheet aligning unit are omitted.

FIG. 3 is a side view of the sheet stack height detecting device of the present invention, taken along arrows BB shown in FIGS. 1 and 2;

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Sheet stack height detection device 2 ... Collection tray 3 ... Holding unit 4 ... Alignment unit 5 ... Deflection panel 10 ... Touch device 11 ... Sensor 12 ... Drive unit 20 Support surface 21 Sheet stack 22 Front locking plate 23 Side locking plate 30 Separating finger 31 Output drive roller 32 Drive Belt 33 Drive roller 34 Drive motor 40 Impeller 41 Output drive roller 42 Drive belt 43 Drive roller 44 Drive motor 100 Touch finger DESCRIPTION OF SYMBOLS 101 ... Search element 102 ... Switching tab 104 ... Spring element 105 ... Support body 107 ... Operating lever 109 ... Locking piece 110 ... First sensor 120 ... Stepper Motor 122 ... Holder 123 ... control cam 124 ... gear 125 ... radial cam 127 ... switching cam 128 ... second sensor 129 ... detection mark x ... conveyance direction y ... start position of the tentacle y ': detection position of fine edible oil z: detection position of the support z': initial position of the support z ": removal / input position of the support

Continued on the front page (72) Inventor Jochen Her Göreber 73266 Bissingen, Germany, Galtenstraße 3 (72) Inventor Volker Her Konig, Germany 73061 Ebersbach, Germany Memel 11, 11 (72) Invention Heinz Michels 72649 Wolfschlugen, Germany, Great Zinger Strasse No. 10/1

Claims (1)

[Claims] 1. A sheet stacking body along a stacking direction of sheets
Drive unit toward (21), and eventually to the detection position
(12) Tactile device (10) controlled and driven by the control unit, and sensor (11) for detecting the height of sheet stack (21) and recognizing the detection position of tactile device (10) And the stack of sheets (2) in the collection tray (2)
In the device for detecting the height of 1), by providing a controllable stepper motor (120), the tentacle (10) can be set from an initial position (y, z ') where it can be set in advance to the sheet stack (2
The stepper motor (120) is moved toward the detection position (y ', z) toward 1) by the stepper motor (120) and is detected from the initial position until the detection position of the tentacle (10) is recognized. The height of the stack (21) is determined based on the step rotation speed of the step (120).